There is a problem in measuring the power output of laser beams. For example, a highly intense laser beam may over saturate and destroy known energy detectors and power meters with the exception of large heat sink spherical calorimeters which totally blocks the beam. When the beam energy was spread over a large area, the ratio of the area of the beam to the detector area was so large that accurate and reliable power measurements could not be made due to inhomogeneties in the beam.
The device of the present invention accurately and reliably measures the beam power without blocking the beam.